The present invention is in the field of automated assembly of articles made from limp material, and more particularly to systems for folding limp material.
Conventional assembly line manufacture of seamed articles constructed of limp fabric consists of a series of manually controlled assembly operations. Generally tactile presentation and control of the fabric-to-be-joined is made to the joining, or sewing, head under manual control. One drawback of this application technique is that the technique is labor intensive; that is, a large portion of the cost for manufacture is spent on labor. To reduce cost, automated or computer-controlled manufacturing techniques have been proposed in the prior art.
An automated approach to fabric presentation and control is disclosed in U.S. patent application Ser. No. 345,756. As there disclosed, pairs of belt assemblies are positioned on both sides of a planar region adapted for passage at the fabric, referred to as the fabric locus. The respective belt assemblies are driven to selectively provide relative motion along a reference axis to layers of fabric lying in the fabric locus. A joining, or sewing, head is adapted for motion adjacent to the fabric locus along an axis perpendicular to the reference axis. The respective belts maintain control of the limp fabric in the region traversed by the sewing head, with the respective belts being selectively retracted, permitting passage therebetween of the sewing head as it advances along its axis of motion. With this approach, control of the limp fabric is permitted in the regions which are to be joined.
In the above-referenced application PCT/US84/00378, a folding system is disclosed in conjunction with a seam joining assembly. That folding system incorporates a three-degree-of-freedom robot arm operating in conjunction with an adjustable beam having a plurality of fabric grabbing devices, and a vacuum table. This configuration, as disclosed, is used to achieve a desired fold geometry for a limp material segment which may then subsequently be presented to a sewing head for seam joining operations. That system is particularly effective for establishing fold geometry with relatively small cloth assemblies.
In addition to relatively small cloth assemblies, for example, sleeves, it is becoming increasingly important in the clothing industry to provide automated folding of relatively large cloth assemblies, for example, pants or coats. With prior art techniques, large cloth assemblies typically require relatively large seam joining machine throat operation, requiring complex mechanisms. The use of prior art techniques have not addressed such problems in a manner to provide the optimal system for such large assemblies. In systems utilizing vacuum tables and a robot arm, relatively high degrees of beam accuracy and alignment are required together with relatively high air handling capability for appropriate vacuum levels. Moreover, field-of-view optics limitations place severe size constraints on systems incorporating vision or image feedback in automated assembly operations.
Accordingly, it is an object of the present invention to provide an improved system for folding material segments.
Another object is to provide an improved system for folding relatively large limp material segments with a high degree of precision.
Yet another object is to provide a system for folding limp material segments with relatively low energy utilization and low cost components.
Still another object is to provide a system for folding limp material segments which is readily adaptable for use with a modular in-line automated garment assembly system.
A further object is to provide an improved system for folding material segments in a manner providing a relatively small required range of motion for a seam joining apparatus.
A still further object is to provide a system for folding material segments including improved orientation and alignment detection for the segment relative to the desired fold geometry.